// from https://raw.githubusercontent.com/gcc-mirror/gcc/master/libgcc/config/epiphany/mulsi3.c

/* Generic 32 bit multiply.
   Copyright (C) 2009-2020 Free Software Foundation, Inc.
   Contributed by Embecosm on behalf of Adapteva, Inc.
This file is part of GCC.
This file is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.
This file is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

unsigned int __mulsi3 (unsigned int a, unsigned int b)
{
  unsigned int r = 0;

  while (a) {
      if (a & 1) {
        r += b;
      }
      a >>= 1;
      b <<= 1;
  }
  return r;
}
